Electrolyte Imbalances and the Impact on ECG Waveforms
Electrolytes are essential for the everyday inner workings of your body and are obtained through the foods you eat and the liquids you drink. They are an important part of water balance, acid/base balance, movement of nutrients and waste across cell membranes, and are an integral part of electrical activity in your body. They maintain a fine balance that allows nerves to transmit signals throughout your nervous system, muscles to contract and relax and play an important role in maintaining cardiac function.
Alterations in various electrolytes such as potassium, sodium, magnesium, and calcium can have a significant impact on the electrical activity of the heart and in some situations can lead to lethal arrhythmias such as ventricular tachycardia and torsade de pointe or can potentiate cardiac rhythms that can lead to cardiac arrest such as changes in the QT interval.
Characteristic changes associated with potassium levels greater than 5.5 mmol/L include peaked T-waves and can lead to widening of the QRS complex, ventricular tachycardia/fibrillation; while potassium levels lower than 2.7 mmol/L can result in increased premature ventricular beats, T wave flattening and inversion. Critically low potassium levels of less than 1.7 mmol/L can result in torsade de pointes1
Another important cardiac electrolyte is magnesium. Elevated levels of magnesium can result in a depressed level of consciousness, bradycardia, cardiac arrhythmias, hypoventilation, and cardiorespiratory arrest while critically low magnesium levels can cause cardiac arrhythmias such as torsade de pointes and other possible symptoms such as muscle cramps and spasms, ataxia, vertigo, seizures, and difficulty swallowing2.
Calcium is yet another electrolyte that when not in balance can cause lethal arrhythmias. Levels greater than 2.7 mmol/L are considered elevated with levels greater than 2.4 mmol/L indicating severe hypercalcemia and can result in shortening of the QT interval and resultant ventricular fibrillation3.
Advanced monitoring is standard in ICUs, yet nearly half of all adverse events in hospitalized patients occur in the general care ward where current monitoring protocols typically consist of intermittent spot checks about every 4-8 hours.
This leaves patients unmonitored for most of the time where subtle abnormalities in vital signs go undetected until complications arise. Studies have shown that continuous vital signs monitoring is associated with significant improvements in key clinical outcomes in patients treated in the general care ward.
ViSi Mobile's constant surveillance monitoring also monitors ECG and arrhythmias, alongside blood pressure, skin temperature, heart rate, SpO2, posture, pulse rate, and respiration rate, as well as to detect potential falls. It improves patient safety by utilizing machine learning from millions of hours of patient data to recognize patient deterioration while minimizing alarm burden and maximizing clinical workflow.
Sources:
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6932546/
- https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.105.166563
- https://www.saem.org/about-saem/academies-interest-groups-affiliates2/cdem/for-students/online-education/m3-curriculum/group-electrocardiogram-(ecg)-rhythm-recognition/electrolyte-abnormalities